gistfile1.rb

#!/usr/bin/env ruby

require 'optparse'

utf8   = true
colors = false

opts = OptionParser.new("", 24, '  ') do |opts|
  opts.banner = "Usage: #{$PROGRAM_NAME} [options] [directory]"

  opts.separator "Directory defaults to the current working directory."
  opts.separator "Options:"

  opts.on('-u', "--[no-]utf8", "use utf-8 for output (defaults to utf8)") { |use|
    utf8 = use
  }

  opts.on('-c', "--[no-]colors", "color output (defaults to no-colors, colors require ANSI capable terminal)") { |use|
    colors = use
  }

  opts.parse! ARGV
end

directory = ARGV.first || Dir.getwd
entries   = Hash.new(0)

if utf8 then
  straight  = "\342\224\202\302\240\302\240"
  node      = "\342\224\234\342\224\200\302\240"
  last_node = "\342\224\224\342\224\200\302\240"
  nothing   = "\302\240\302\240\302\240"
else
  straight  = "|   "
  node      = "|-- "
  last_node = "`-- "
  nothing   = "    "
end

# Find all paths and sort them
glob  = Dir.chdir(directory) { Dir['**/*'].sort }.sort_by { |path|
  path.split(File::Separator) # change this to change sort order, e.g. could implement case insensitive sorting
}

# Prepare for drawing the proper lines at the right place
glob.each do |path| entries[File.dirname(path)] += 1 end

# Print the tree
puts File.expand_path(directory)
glob.each do |path|
  dir,file      = File.split(path)
  entries[dir] -= 1
  prefix        = (entries[dir].zero? ? last_node : node).dup

  until dir == '.'
    dir         = File.dirname(dir)
    prefix[0,0] = entries[dir].zero? ? nothing : straight
  end

  # Color the output
  if colors then
    stat       = File.stat(File.join(directory,path))
    foreground = case
      when stat.file?      then nil
      when stat.directory? then 34
      when stat.symlink?   then 32
      else                      nil
    end
    background = nil
    file       = "\e[#{[foreground,background].compact.join(';')}m#{file}\e[0m"
  end

  puts "#{prefix}#{file}"
end